Artificial foot.



C. B. WINN.

ARTIFICIAL FOOT.

APPLICATION FILED JUNE 24. I918.

Patented Nov. 26, 1918.

CHESTER B. WINN, OF BUFFALO, NEW YORK.

ARTIFICIAL FOOT.

Specification of Letters Patent.

Patented N 0V. 26, 1918.

Application filed June 24, 1918. Serial No. 241,487.

To all whom it may concern:

Be it known that I, CHESTER B. WINN, a citizen of the United States,residing at Buffalo, in the county of Erie and State of New York, haveinvented new and useful Improvements in Artificial Feet, of which thefollowing is a specification.

The principal object of my invention is the provision of an artificialfoot which closely imitates the movements of the human foot under theweight of the wearer in walking, running, going up and down stairs andin all other acts necessary to locomotion.

Further objects are to accomplish this re sult with a minimum number ofparts and in such a manner as to produce a comfortable action and avoidundue flopping of the foot or jarring of the wearer.

In the accompanying drawings:

Figures 1, 2 and 3 are vertical longitudinal sections of an artificialleg embodying the invention, showing different positions of thefoot-members. Fig. 4 is a transverse section on line H, Fig. 1. Fig. 5is a transverse section of a modified construction of the improvement.

Similar characters of reference indicate corresponding parts in theseveral views.

1 indicates the shin or ankle-piece of the leg and 2 a resilient heel orheel-cushion having its upper endglued or otherwise secured to theankle-piece and consisting of sponge rubber or other suitable material.This heel preferablyv extends well up on the rear side of theangle-piece and meets the same in any oblique joint 3 sloping from theback of the ankle-piece to its lower end, as shown.

Arranged on the underside of the anglepiece in front of the resilientheel is a rockin ball-section or foot-piece 4 of rigid materia as wood,which is wholly disconnected from the heel 2. This foot-piece extendsfrom the front side of the heel preferably to a point somewhat short ofthe toe of the foot, the part beyond the foot-piece consisting of atoe-portion 5 of sponge rubber, felt or other resilient material. Thefoot piece is fulcrumed between its ends on the underside of theankle-piece, the ,preferred means for this purpose being a roundedtransverse rib or journal 6 carried by the ankle-piece and seated in acorresponding groove or recess 7 in the upper side of the foot-piece.The latter is held in position by a substantially upright bolt 8 passingthrough the closed bottom of the hollow an- I kle-piece and the portionof the foot-piece on the rear side of its fulcrum, the bolt holes ofthese parts being flared, as shown, to permit the-free articulation ofthe foot-piece 011 the ankle-piece. Interposed between the washer 9 ofthe bolt and the opposing surface of the ankle-piece is a spring orcushion 10 of rubber or metal, which yieldingly resists downwardmovement of the rear end of the rocking foot-piece. A cushion 11 ofsponge rubber-or other suitable material is interposed between the frontportion of the foot-piece and the ankle-piece to likewise resist upwardmovement of the foot-piece. The cushion 11 may be partly seated in arecess 12 in the upper side of the foot-piece and glued to the latter orthe ankle-piece or both of these parts. 1

As shown in the drawings, the usual nose or forward projection on thebase of the am kle-piece is preferably cut away, leaving an abruptsubstantially upright face 1 on the front side of the rib 6 againstwhich the rear end of the cushion 11 bears.

The toe-portion 5 is glued to the foot-piece and may be furtherconnected thereto bya strip of canvas 13. Y

If desired, the foot-piece may be constructed to tilt laterally, as wellas rock vertically. A modified construction of this characterisillustrated in Fig. 5, where the underside of the fulcrum-rib 6* isrepresent ed as being curved lengthwise or gradually reduced in depthfrom its center toward both ends, while the groove or recess in thefootpiece is of uniform depth from end to end. This construction permitsa practically universal movement of the foot-piece on the ankle-piece.Excessive transverse rocking or tilting of the foot-piece is prevented ya pair of rubber blocks 14 or other approprlate cushions arranged inopposite ends of. said groove.

In the drawings, the usual leather covering of the foot is omitted, forclearness.

Fig. 1 shows the position of the parts when the foot is wholly relievedfrom the wearers weight. When the wearer takes a forward step with theartificial leg, the resilient heel 2 is compressed upward and itsbase-portion is deflected backward, as shown in Fig. 2, separating itfrom the foot-piece 4, with the result that the latter is brought downin a natural manner and a forward impetus is given to the leg. The\vearers weight then shifts to the ball or foot-piece, whose frontportion is thereby swung upward, while its rear portion is depressed, asshown in Fig. 3, bringing the strain on the rear or bolt'cushion 10 andthe front cushion 11 and compressing the same. Finally, the weight isreceived by the resilient toe-portion 5. These movementsproduce an easy,graceful and comfortable step, the action of the foot, both mechanicallyand in appearance, closely imitating that of the human foot. This resultis most satisfactorily obtained by placing the fulcrum of the footpiecewell forward on the ankle-piece, as shown in the drawings.

By this construction, only the foot-piece is in action during suchforward movement, which feature promotes natural and easy walking and isa marked departure from the movement obtained by fulcruming the entirefoot on the ankle-piece.

This desirable action of the foot-piece and the heel is secured largelyby the complete separation or disconnection of these parts, whichconstruction permits independent movement of either part withoutrestraint by the other. This separate and independent construction ofthese parts also permits the front portion of the foot-piece to beregulated or adjusted up or down relatively to the heel, by means of thebolt 8, to meet different conditions. Any space left between the rearpart of the foot-piece and the anklepiece by such adjustment may befilled by a shim-15 of sponge rubber or other suitable material.

I claim as my invention:

- 1. An artificial f00t,'COl11PIlSll1g an nklepiece, a foot-piecefulcrumed between its ends on the ankle-piece, and a heel of resili entmaterial secured to the ankle-piece, the foot-piece being whollyseparate from the heel and free to articulate independently thereof andthe front portion'of the heel terminating at the rear end of thefoot-piece and being disconnected therefrom.

An artificial foot, comprising an anklepiece, a foot-piece fulcrumedbetween its ends on the ankle-piece, a bolt connecting the ankle-pieceand foot-piece on the rear side of the fulcrum of the latter, a cushionapplied to said bolt, a second cushion interposed between the foot-pieceand the anklepiece on the front side of said fulcrum, and a heel ofresilient material secured to the ankle-piece and disconi'iected fromsaid footpiece.

3. An artificial foot, comprisingan ankle piece having its base providedon. its under side with a fulcrum-rib and in front. of said rib with asubstantially upright face, a footpiece fulcrumed on said rib, aretaining bolt passing through the bottom of the anklepiece and theportion of the foot-piece in rear of said fulcrum-rib, and a cushioninterposed between said upright face and the upper side of thefoot-piece.

4. An artificial foot comprising a footpiece having a transverse groovein its upper side, an ankle-piece provided on the underside of its basewith a transverse fulcrum-rib seated in said groove, said rib having aconvex bottom-face extending lengthwise there of and resting upon thebottom of said groove, and means for retaining said rib in said groove.

5. An artificial foot comprising footpiece having a transverse groove inits upper side, an ankle piece provided on the underside of its basewith a transverse fulcrum-rib seated in said groove, saidrib having aconvex lower edge extending lengthwise thereof and bearing upon thebottom-of said groove, means for retaining said rib in said groove, andcushions seated in opposite ends of the groove to resist transversetilting of the foot-piece.

CHESTER 1e. wrnu.

Copies of this patent may be obtained. for five cents each, byaddressing the Commissioner of Patents, Washington, I). G.

